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BoKu

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Exactly. If he listened to all the engineers he would not even consider an auto diesel or canard or anything as a first try. But his engineer stuck with it.
And it has worked for several months so far.
If he had listened to engineers he would have done what they do at SpaceX and Scaled Composites:

* Instituted rigorous weight controls so that he has reasonably accurate estimates for the weight of every component and can make responsible decisions about what features to include and what to leave out. He would have been using the materials mass estimation features in his CAD software from day 1, and weighing each off-the-shelf component as it arrived, and using reasonable mass estimates for other things. That would have saved him the huge disappointment of finding out how heavy the thing is so late in the program when there is little to be done about it.

* Considered the elastic properties of all assemblies, and especially for the control system. That plus some judicious breadboarding would have saved him several frustrating iterations of primary control system design. At the heart of this particular tidbit is the misguided use of extremely short cable travels, and consequently high cable tensions, which made stiffness extra important--stiffness that was notably lacking in his TLAR'd system anchors.

* Started simple, within the cloud of established practice, and innovated from there. Imagine if Peter had just bought a Velocity kit and an IO-540, reverse-engineered a slightly wider fuselage from carbon, and added pressurization once he had it flying. If he followed those other two bits of engineering advice, he probably would have pulled it off and had the 25,000-foot cruising altitude so critical to his performance claims. He could then build upon that foundation of success with some judicious powerplant innovation.

Yes, you are correct. I didnt remember that. That sort of proves my point. I don't trust the engineering team effort on this.
If he had followed the engineering guide for the torsional damper, he would have used a much larger unit with beefier attachment. The one he chose is being used well above its torque and RPM specs.

Why doesn't the engineer just tell him to suspend any test flights and move to an airplane engine instead of helping redesign the PSRU each time?
There is no "the engineer." There is only Peter, and he regards and disregards engineering advice from a variety of sources at his convenience.
 

pictsidhe

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Kyle Boatright

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Interesting. Not sure it is in their interests to publicise that. The CFD analysis on the Raptor site shows the SR22 as needing several times the power it actually has...
You've gotta parse words carefully.

Creative Flight Designs is a company which did some work for Peter.

Computational Fluid Dynamics is a process, generally using off the shelf software, to estimate aircraft performance.

I'm betting the CFD you're talking about (edit - on the Cirrus) was the second kind and was carried out by someone who didn't know what they were doing or they would have gotten reasonable results.
 
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ScaleBirdsScott

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I'm no lawyer but an engineer or designer can provide all the designs in the world to a client, it's still up to the client to execute in accordance with the design they paid for. If the client paid for an executed design that's one thing. And certainly there is a logic to turning down projects that seem risky.

But there's also the mentality of "If I don't step in and do it right, someone else is probably going to do it wrong," and I'm sure countless other reasonings, in which someone might try and step into a project with novice "dreamer" types.
 

Jet787

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Hubris, just like the Capt. of the Titanic
My quip was meant to be humorous but in all seriousness the Capt of the Titanic had 37 years for sailing experience, 20 years as captain and had the highest credentials. Peter on the other hand is a ~400 hr flight instructor (as far as I know) with limited recent flight time and no canard experience that he has mentioned. He is seriously beyond his capacity. During the aileron flutter incident on the taxi run, in the cockpit view he can be seen frantically cycling between full left to full right aileron control. In the first hop video on the cockpit view he is again over controlling in pitch. In the second hop video he omits the cockpit view (I suspect that it was unflattering) but in the exterior view one can see his over controlling in pitch. In each of the videos his hand is shaking as he reaches for the controls. This is a sign of an overloaded pilot. You fly airplanes with pressure on the controls not movement of the controls. Student/inexperienced pilots fly with movement of the controls and commonly induce PIO. In his first hop he misidentified a minor roll to the right which was probably self induced as a weight imbalance and jerry-rigs weights to the winglets?
As a Capt of a large transport aircraft with the lives of 300+ people onboard I’m not paid hundreds of thousands of dollars per year for the thousands of flights that go well. I’m paid for the one time that the spaghetti hits the fan (the center engine blows up and takes out all of the hydraulic flight controls or a flock of birds take out both engines).
Peter has demonstrated that he does not have the experience or the excess capacity to handle a serious event. Take your pick of any of the valid issues that have been addressed on this forum (redrive failure, turbo/engine failure, winglet ripping off, wing or aileron flutter, etc).
I doubt that he will handle it well. I hope he survives.
 

Speedboat100

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The problem is all the pieces and parts are going to cost that. He has already stated he doesn't know much about getting the kits produced. So, best case scenario is the thing flies perfect, he gets the redesign done with reduced weight with the $2.5 million escrows and some investor(s) comes in with help to fund production. The business side is where all this falls...... well, except physics. No one is handing you $5 million and turn around and selling kits at costs. They are going to want to make their investment back in a reasonable timeframe. Pretending this thing worked, it's an easy $300k kit. Just look at what a Lancair Mako costs, a loaded up kit without the engine is $430k.

Well I meant making the kit complete with 130 K USd was a bit optimistic...and you agree.
 
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wsimpso1

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That's one company. I believe the majority of German gliders and motorgliders have solid fuselages. Ask Boku? I think pressurized dictates solid core less, at least the cockpit.
While some outfits make fuselage walls solid, and some pressurized vessels are solid, pressurized does not dictate solid. SpaceShipOne is a double hull of carbon fiber laminate on either side of a core. Yes, total double hull. Two layers of shell, windows, doors. Supposedly SpaceShipOne is three plies of 6 oz twill fabric on each side, so it is not heavy. And remember, it did collapse the gear and go off the runway in a huge cloud of dust. They fixed it in a few days and broke all of the X-15 records, so it is not exactly fragile that way...

Something to remember about sandwich composites - we split the composites and put them on either side of a core to increase bending stiffness and strength of panels without using a bunch more cloth and resin. Go to sailplanes - like race cars and ag planes - the designers expect them to be crashed. Competition sailplanes hit each other, land out in less than ideal places, and sometimes thump onto terrafirma in unceremonious ways. Protecting the crew anyway is part of the program, so sailplanes tend to have significantly more substantial laminates through the cockpit than is needed just to carry flying loads. Once you have your crashworthiness covered, these skins tend to have excess bending strength and stiffness and there becomes no point in a core in many of them.

At a Ford Technical Specialist Symposium, I listened to a Boeing Vice-President tell us about the development of the 787 fuselage design, and how they considered aluminum, solid laminate, and sandwich laminate, established their criteria for evaluation of all, and ultimately chose solid laminate.

The criteria in each case is to determine what strengths and stiffnesses you need and finding the lightest way of getting there. Sometimes a cored part is the way, sometimes not.

I don't know what Peter's initial projection was, but I doubt that any hired engineer would neglect to ...
Must we continue with the speculation on motive and talent? Let's stay on the airplane here folks...

Billski
 
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cheapracer

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The plane weighs around 1600 pounds more than Peter's initial projection. It will have about 30% more drag than he thinks. The engine will burn 50% more fuel than he projected, make 50% less hp than he thinks he has, range will be 75% less and it will cost at least 100% more than his projections- all in round figures. It will never go into kit production with the Audi diesel engine, the scary PSRU and nonsensical turbo system. This says nothing of the likely stability, handling, control and structural issues that will need serious sorting and time consuming and costly modifications.
..........
 

wsimpso1

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I just deleted a bunch of posts. The authors of the deleted posts know who you are and why I deleted them. HBA.com is rare island of civility. Let's keep it that way.

We are all wise to re-visit the code of conduct periodically. Below is attached the code of conduct we all agree to while remaining on this forum.


Billski
 

AdrianS

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<snip>

Must we continue with the speculation on motive and talent? Let's stay on the airplane here folks...

Billski
While I agree with you as I quoted, there is something to learn about the approach to design.

I design and write software for a living.
I have several times slapped temporary "bandaid" code in a development project - it's ugly, and the program may run very slowly and use a heap more memory - but it runs, and can be used to test an idea, often on a much higher spec machine than the target platform.

I believe that's the world PM comes from too.

(As my code controls machinery that can kill people, the ugly bits get redone, or the whole thing redesigned, before it gets anywhere near actual hardware. It's then thoroughly tested before it gets near nasty spinning metal.)

An aeroplane has to fly, safely, first time up.

If it's too heavy, underpowered, unstable, or unreliable, people can get hurt.

There's a fundamental difference in approach required.
 

pictsidhe

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I'm no lawyer but an engineer or designer can provide all the designs in the world to a client, it's still up to the client to execute in accordance with the design they paid for. If the client paid for an executed design that's one thing. And certainly there is a logic to turning down projects that seem risky.

But there's also the mentality of "If I don't step in and do it right, someone else is probably going to do it wrong," and I'm sure countless other reasonings, in which someone might try and step into a project with novice "dreamer" types.
When a client thinks that "I don't think so" is better than my maths or experience, I have found it best to walk and let them try and find someone else. They find that difficult, for reasons that they don't understand. You can't help people who won't listen.

One boss many years ago wanted me to repair some chewed up slip rings in an alternator. I measured up and asked for a suitable hunk of copper. He told me to use water pipe. I tried to tell him it was way too thin and soft, it would only last a thousand miles. He was absolutely furious at me when it self destructed after 1500.

Performing client specified kludges on an aeroplane? You couldn't pay me enough.
 

Pilot-34

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While I agree with you as I quoted, there is something to learn about the approach to design.

I design and write software for a living.
I have several times slapped temporary "bandaid" code in a development project - it's ugly, and the program may run very slowly and use a heap more memory - but it runs, and can be used to test an idea, often on a much higher spec machine than the target platform.

I believe that's the world PM comes from too.

(As my code controls machinery that can kill people, the ugly bits get redone, or the whole thing redesigned, before it gets anywhere near actual hardware. It's then thoroughly tested before it gets near nasty spinning metal.)

An aeroplane has to fly, safely, first time up.

If it's too heavy, underpowered, unstable, or unreliable, people can get hurt.

There's a fundamental difference in approach required.
Yes I think that’s part of the problem Peter has come from similar backgrounds where they can put a nasty patch on something

On the other hand If I build something out inch and a half steel its a lot tougher put a patch on it cut the patch ,put a new patch over it cut that out grind that put put a new patch on top of it cut that out with a torch patch it again and still be able to use that base area.
I don’t think Peter is used to the idea of the prototype being disposable
 

poormansairforce

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I don’t think Peter is used to the idea of the prototype being disposable
This is exactly what I've been saying all along. He never allowed for a second or third prototype because he was convinced he was building the real deal so therefore there are no funds available for a redo. And there will be less available once the performance targets are not met.
 
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Steve C

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I've seen a tailboom repair on a relatively modern sailplane. It most certainly had a core in it. No idea what's up in the cockpit area.
 

cheapracer

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Exactly. If he listened to all the engineers he would not even consider an auto diesel or canard or anything as a first try.
And it has worked for several months so far.
It has had belt failures, damper coupling failure, and multiple tunes, and the famous "stall" for Wasabi, so no, it hasn't "worked for several months so far".

Sure, there has been no, and should not be issue with the core itself, it's a well proven, Audi mass produced engine, it's the torsional vibrations it develops that is questionable long term to everything around and attached to it, and little doubt responsible for the damper coupling failure.

... and then there's the weight, we see how that's working out, it's a good chunk of that 3600 lbs (with pilot) ...


I don’t think Peter is used to the idea of the prototype being disposable
Exactly. I doubt it ever entered the thought train that the Proto will end up on display, or gathering dust in a corner for the rest of it's life.
 

pictsidhe

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Actually, the core engine is now at high risk of failure thanks to Peter's turbocharging and injection 'upgrades' .

He has raised peak cylinder pressures and EGT. He is monitoring neither, just TIT, which going to be a bit lower than EGT. How much lower is subject to various factors. Audi measures cylinder pressure for these engines, so they have the sensor to do that already there. It is plain foolish to attempt to increase power without monitoring cylinder pressure and EGT.
 
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berridos

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After 50 hours he should dissamble the engine to review the crankshaft for plays produced by torsional vibrations. Guess 50 hours of bouncing around are already over. Would be an episode worthwhile to watch
 
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